Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only supply idempotentHint and destructiveHint=false, so the description carries most of the behavioral load and does so well: login requirement, 403 on editing someone else's entry, null-to-clear semantics, and the explicit distinction between omitting contribution and clearing it. That is solid added context beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Dense but front-loaded: the core action and the null-clear option come first, followed by the workflow and permission caveat. A few clauses repeat the schema's contribution description, but overall every sentence carries operational value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple three-parameter setter with no output schema, the description covers authentication, permission rules, the pre-read workflow, verification, and the clearing semantics. An agent has everything needed to call it correctly and interpret failures.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 67% (userId and contribution are documented, goalId is not). The description reinforces the ≤60-character limit and, more importantly, explains that null clears while omission is invalid — a semantic nuance not fully obvious from the schema. goalId is left implicit but is self-evident from context.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: write what a person is responsible for within a goal, with a 60-character cap. It is clearly distinguishable from siblings like update_collaboration_goal (edits the goal itself) and invite_collaboration_member (adds members at invite time).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says when to use it (when contribution wasn't written at invite time and was decided later) and gives the exact workflow: get_collaboration_goal to fetch members[].userId and myAccess, then this tool, then re-read to verify. It also states the permission boundary — collaborators may only edit their own entry, otherwise the goal initiator is required or a 403 results.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.